Safety lock for elevator doors



B. C. VAN EMON AND W.'A. WOLF.

SAFETY LOCK FOR ELEVATOR DOORS.

APPLICATION FILED ocT. 2'5. 1920.

1 ,42 1 ,O43 Patented June 27, 1922'.

2 SHEETS-SHEET l.

WMO 5.,

B. C. VAN EMON AND W. A. WOLF.

SAFETY LOCK FOR ELEVATOR DOORS.

APPLICATION FILED ocT. 25. 1920.

1,421,043. Patena June 27,1922.

`2 SHEETS-SHEET 2.

IIIQQIQIIIIII BIRF-CTION S\VITCH I v A. WOLF. GF ALAMEDA,

SAFETY LOCK FOI?.` ELEVATOR DOORS.

Specification of Letters Patent.

Patented June` er. 1922..

Application led October 25, 1920. Serial `No. 419,505.

To all wibo/m, t may concern.'

Be it known that BURTON C. VAN Eaton and Turnen A. IVQLF. citizens of the United States of America, residing at San Francisco and Alameda, respectively; in the county of `SanFrancisco and Alameda and State of California, have invented certain new and useful Improvements iny Safety Locks for Elevator Doors, of which the tollowing -is a specification.

The present invention relates to safety door locks for automatic elevato-rs and more particularly to that type ot lock in Vwhich a guard element is used-to prevent the release of the latch on thel elevator door until the elevator has come to a full stop at 3a predetermined floor.

In devices of this characte'r, -now in use, the guard releasing' mechanism is `usually controlled by camsor otherjobstructions attached to the car and Vadapted to travel therewith or fixed -to the shaft and arranged to project into the pathof travel of .the car. The primary object of oui` invention is todispense with camson the car and with contacting mechanism in the path of travel of the car. f

Another object is to increase the factor of safety automatic elevators by providing an electrically controlled guard mechanism in which both ends of the controlling circuit are open at all times except when the elevator reaches-the predetermined stopping point and in which all .danger from grounding the circuit is eliminated. In our device hereinafter described. we eliminate all trips, cams, and the like from the path of travel and substitute .therefor a circular cam wheel geared to or suitably driven by the drum shaft and the entire mechanism is easily coordinated with and attached to conventional elevator apparatus.

In this specification and the annexed drawings, the invention is illustrated inv the form considered to be the best, but it is to be vunderstood that the invention is not limited to such form, because it may be embodied in other forms and itis also to be understood that in and by claims follow ing `the description it is desired to cover the invention 'in whatever form it may be embodied.

I In the accompanying two sheets of draw ings Fig. l an elevation of a cam wheel and a disc for supporting liXed contacts iirrelation thereto.

Fig. 2 is a of Fig. l.

F ig. 3 is a central cross section of our lock showing the actuating mechanism controlling the latch guard.

Fig. 4f is a section kof same on the line IV-IV'O Fig. 3.

Fig. 5 is a fragmentary section of a switch board showing a yswitch adapted `to be actuated by the direction switch of an elevator. Fig. 6 is a central cross section on a line lTI-VI of Fig. 7'. I

Fig. 7 is a side elevation ota dash pot controlled by a solenoid Jfor introducing a time element land Lresistance cut in a circuit.

y Fir. 8 is a diagram of the wiring in our central vertical cross section invention. y v

In the ,presentv yembodiment of `our invention the numeral l, Fig. 3, indicates a casing of vany suitable shape here shown as rectangular which is adapted to be itted in place on a door frame and vcontain thelock mechanism hereinafter described.r

The' casing l is pro-vided with the usual opening 2 through which the hook v.end of a latch 3 may enter for engagement of the f door with the lock. The latch 3 is lpivo'ted to the door as indicated at 1i. n

Pivoted iat 6 is an elbow lever, the lower member 7 of which serv-es as a guard to secure the latch 3, when in locked position, as shown in Fig. 3. The other member 8 of the lever serves as anA armature. and is adapted to be actuated by. an electromagnet 9 t'ed by wires l1 and 12. When the magnet 9 is energized the elbow lever is drawn .to the dotted position shown in Fig. 3 and the latch 3 is free to disenga'ge from the casing l. The'lock is provided with the usual `door switch to prevent operation of the car when a 'door is open. yAlever 13, pivoted at 14 an-dprovi-ded with an integral weighted portion 16, normally hangs in the dotted position shown in Fig. 3, but the added weight of kthe hook end of the latch 3 depresses the lever .to the full line position and causes 4 In Figs. 1 and 2 we show a mechanism for coordinating the electric lock control with a conventional floor stop device.

Angle irons 21 and 22 are secured as by rivets to an inverted channel iron 24 to form a base to which is secured a standard arm 26 bored to receive a shaft 27 which may be the operating shaft of a floor stop device or may be suitably geared thereto or driven thereby. y

Secured to the standard 26 in fixed relation thereto, as indicated by set screw 28, is a disc 29. Radially disposed on the periphery of this lixed disc are make and break contacts in number corresponding to the number of floors served by the elevator and here shown at A B and G.

Keyed as shown at 31 to the shaft 27 is a cam disc 32 adapted to close the circuit by making contact successively at A B and C when turned in either direction by the floor stop device.

The make and break contacts are all alike and but one will be described. A U-shaped member 33 is adapted to straddle the periphey ot the disc 29 and is secured thereto by set screws 35. Secured to said member 33 as by screw 34 is a piece o'f insulative material 36, to which is secured a metal platform 38 having npstanding lugs 39, 41., through which said lugs extends a pintle pin 42. On this pin is pivoted an elbow lever 43 of conductive material. One end of the said elbow lever is adapted to contact with a spring pressed carbon 44 supported by the platform 38.

The platform 38 is providedwith terminals 46, 47, to which the wires of the circuit which it is desired to make and break are secured.

The lower end ot lever 43 is turned down to form a shaft for a roller 48 oit insulative material, and of a diameter slightly less than the width of the cam track 49 of wheel 32. The said wheel has a cam segment as shown at 51 adapted to raise and lower the wheel 48 by contacting on alternate sides thereof during the travel of the cam portion of the track past the fixed wheel, and by so doing make and break contact between terminals 46 and 47.

By referring toFig. 8 it will be seen that the circuit controlling the magnet in our lock is governed by the direction switch, here shown diagrammatically at 52 and 53 to indicate respectively the upward and downward movement of the car. ln our device the direction switch opens the teed eircuit and demagnetizes all locks. This is accomplished by the device shown in Fig. 5 in which a fragment 54 of the switchboard is shown. Terminals 56, 57 secure angle pieces 58, 59 of conductive material to the board 54. These terminals are normally connected through a contact plate 61 which is held in contact with said terminals by an expansion spring 62 in a plug 63. A push contact 64 ott insulative material is pushed toward the switch board as the direction switch is closed. l/Ve provide an apparatus such as shown in Fig. 5 for both switches so that the circuit is broken when the car is started in either direction.

1n order to preclude the possibility oi' overheating the magnet 9 and to keep a small amount of current in the magnet when the car is idle we provide an automatically operated time element which short circuits resistance when the car stops and circuit is closed between 58 and 59.

ln Figs. 6 and 7 this device is shown on the switch-board 54. Secured to the said board by a U-bolt is a tubular housing 67, closedr at the top by a cover 68. An electromagnet 69 is within the housing. The core 7l of thc magnet is centrally bored at 72 for entrance ot a pin 73 loosely secured as by a pin 74 to the core 7l.

The pin 73 is rigidly secured to a plunger 76 loosely fitting within the housing 67. Then the magnet 69 is energized the apparatus is in the position shown in Figs. 6 and 7. lt the magnet is cle-energrrizedl the core and plunger drop by gravity to the dotted position.

Terminals 77, 78 extend through the switchboard 54. On the back of the board these terminals are connected by a suitable conductor which has approximately 3000 ohms resistance as indicated at 79, while on the tace ot the board, the terminals are pro'- vided with metal clips 81,82. Contact is made between these clips and the terminals 7 7, 78 by a metal band 83 surrounding an insulation disc 84 secured to the core 71 by 'a' screw 86. l

It results from this structure that when the car stops full current is sent to the coil in the lock giving it full strength to open the guard and release the latch. The

plunger 76 slowly settles while displacing air1 in the housing 67, breaking the direct ,current and sending same through resistance element 79, allowing a small current tol pass and hold guard open all the time the car is at rest. If a ground should occur one-ircuit to coil in lock the resistance is so `higih that the guard would not lift to release' the door latch.` i

The operation ot an elevator equipped with our device is as follows: When the car is at `rest at a floor, both direction switches 52, 53, are out, which closes the feed circuit to locks. Return circuit is closed by Contact on iioor stop device for this particular ioor.

There is no current flowing to the lock when the car is in motion. 'lNhen the car stops at a floor, circuit is made to that lock and no other. The full force of current energizes the magnet and releases the latch.

Having thus described our invention, What We claim as new and desire to protect by Letters Patent of the U. S. is-

l. In an electrical apparatus for controlling an elevator door lock, an electromagnet, a latch, a guard for said latch, an armature adapted to operate said guard when actuated by said magnet, means for energizing said magnet when the elevator reaches a pre-determined position, and means for maintaining a relativelyY small amount of energy in said magnet While the elevator is at rest to retain the lock in inoperative position.

2. In. an electrical apparatus for controlling an elevator door lock, an electromagnet, a latch, a guard for said latch, an armature adapted to operate said guard When actuated hy said magnet, means for energizing said magnet when the elevator reaches a pre'- l kdetermined position, means for mamtalning a latch to a lock housing comprising an electromagnet secured to said housing, a latch, a guard for said latch, a lever normally locking said latch to said lock housing and adapted to release said latch when said magnet is energized, means for energizing said magnet and means for automatically reducing the energy in said magnet to a quantity sufcient to hold saidlever in inoperative position.

In testimony whereof We aix our signatures.

BURTON C. VAN ELWION. WILFRED A. WOLF. 

